Discovery of the Daba meteorite crater on the southeastern margin of the Dabie Mountains, China

Abstract：This paper introduces a newly discovered meteorite crater in Daba on the southeastern margin of the Dabie Mountains in Anhui Province. Preliminary survey has revealed that the Daba meteorite crater is elliptic in shape with its major-axis oriented in a NNE direction, ~19 km long, and its minor-axis being ~12 km and the maximum depth being 2 km. This is a compound meteorite crater with a central uplift. The Daba crater has a circular image in satellite photos and shows a depression topographically. The base of the Daba meteorite crater is well preserved and its boundary may be directly observed and traced. All types of impact metamorphic rocks formed at ~230 Ma are well developed, of which there are rocks containing typical impact metamorphic minerals such as coesite and typical ultramicro-structures such as impact cataclastic structures and especially desiccation auto-breccia found structure commonly on the inner walls of the crater's base, which serves as the most reliable indication for indentifying the meteorite crater. All the evidence has confirmed that the Daba circular image is a typical meteorite crater structure. This new discovery is of great significance both scientifically and economically. A model may be constructed for guiding further search and investigation of meteorite craters in the folded mountainous areas. Meanwhile, it also greatly enriches the geological evidence for establishing the Dabie Global Geopark. This discovery will undoubtedly promote the development of tourism of the Dabie Mountains as well as popularization of knowledge of meteorite impact.